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/*
 * Copyright (C) 2006 Ondrej Palkovsky
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */ 

#include <ipc.h>
#include <libc.h>
#include <malloc.h>
#include <errno.h>
#include <list.h>
#include <stdio.h>
#include <unistd.h>
#include <futex.h>

/** Structure used for keeping track of sent async msgs 
 * and queing unsent msgs
 *
 */
typedef struct {
    link_t list;

    ipc_async_callback_t callback;
    void *private;
    union {
        ipc_callid_t callid;
        struct {
            ipc_call_t data;
            int phoneid;
        } msg;
    }u;
} async_call_t;

LIST_INITIALIZE(dispatched_calls);
LIST_INITIALIZE(queued_calls);

static atomic_t ipc_futex;

void _ipc_init(void)
{
    futex_initialize(&ipc_futex, 1);
}

int ipc_call_sync(int phoneid, ipcarg_t method, ipcarg_t arg1, 
          ipcarg_t *result)
{
    ipc_call_t resdata;
    int callres;
    
    callres = __SYSCALL4(SYS_IPC_CALL_SYNC_FAST, phoneid, method, arg1,
                 (sysarg_t)&resdata);
    if (callres)
        return callres;
    if (result)
        *result = IPC_GET_ARG1(resdata);
    return IPC_GET_RETVAL(resdata);
}

int ipc_call_sync_3(int phoneid, ipcarg_t method, ipcarg_t arg1,
            ipcarg_t arg2, ipcarg_t arg3,
            ipcarg_t *result1, ipcarg_t *result2, ipcarg_t *result3)
{
    ipc_call_t data;
    int callres;

    IPC_SET_METHOD(data, method);
    IPC_SET_ARG1(data, arg1);
    IPC_SET_ARG2(data, arg2);
    IPC_SET_ARG3(data, arg3);

    callres = __SYSCALL3(SYS_IPC_CALL_SYNC, phoneid, (sysarg_t)&data,
                 (sysarg_t)&data);
    if (callres)
        return callres;

    if (result1)
        *result1 = IPC_GET_ARG1(data);
    if (result2)
        *result2 = IPC_GET_ARG2(data);
    if (result3)
        *result3 = IPC_GET_ARG3(data);
    return IPC_GET_RETVAL(data);
}

/** Syscall to send asynchronous message */
static  ipc_callid_t _ipc_call_async(int phoneid, ipc_call_t *data)
{
    return __SYSCALL2(SYS_IPC_CALL_ASYNC, phoneid, (sysarg_t)data);
}

/** Send asynchronous message
 *
 * - if fatal error, call callback handler with proper error code
 * - if message cannot be temporarily sent, add to queue
 */
void ipc_call_async_2(int phoneid, ipcarg_t method, ipcarg_t arg1,
              ipcarg_t arg2, void *private,
              ipc_async_callback_t callback)
{
    async_call_t *call;
    ipc_callid_t callid;

    call = malloc(sizeof(*call));
    if (!call) {
        callback(private, ENOMEM, NULL);
        return;
    }
        
    callid = __SYSCALL4(SYS_IPC_CALL_ASYNC_FAST, phoneid, method, arg1, arg2);
    if (callid == IPC_CALLRET_FATAL) {
        /* Call asynchronous handler with error code */
        callback(private, ENOENT, NULL);
        free(call);
        return;
    }

    call->callback = callback;
    call->private = private;

    if (callid == IPC_CALLRET_TEMPORARY) {
        /* Add asynchronous call to queue of non-dispatched async calls */
        call->u.msg.phoneid = phoneid;
        IPC_SET_METHOD(call->u.msg.data, method);
        IPC_SET_ARG1(call->u.msg.data, arg1);
        IPC_SET_ARG2(call->u.msg.data, arg2);
        
        futex_down(&ipc_futex);
        list_append(&call->list, &queued_calls);
        futex_up(&ipc_futex);
        return;
    }
    call->u.callid = callid;
    /* Add call to list of dispatched calls */
    futex_down(&ipc_futex);
    list_append(&call->list, &dispatched_calls);
    futex_up(&ipc_futex);
}


/** Send a fast answer to a received call.
 *
 * The fast answer makes use of passing retval and first two arguments in registers.
 * If you need to return more, use the ipc_answer() instead.
 *
 * @param callid ID of the call being answered.
 * @param retval Return value.
 * @param arg1 First return argument.
 * @param arg2 Second return argument.
 *
 * @return Zero on success or a value from @ref errno.h on failure.
 */
ipcarg_t ipc_answer_fast(ipc_callid_t callid, ipcarg_t retval, ipcarg_t arg1,
        ipcarg_t arg2)
{
    return __SYSCALL4(SYS_IPC_ANSWER_FAST, callid, retval, arg1, arg2);
}

/** Send a full answer to a received call.
 *
 * @param callid ID of the call being answered.
 * @param call Call data. Must be already initialized by the responder.
 *
 * @return Zero on success or a value from @ref errno.h on failure.
 */
ipcarg_t ipc_answer(ipc_callid_t callid, ipc_call_t *call)
{
    return __SYSCALL2(SYS_IPC_ANSWER, callid, (sysarg_t) call);
}


/** Try to dispatch queed calls from async queue */
static void try_dispatch_queued_calls(void)
{
    async_call_t *call;
    ipc_callid_t callid;

    futex_down(&ipc_futex);
    while (!list_empty(&queued_calls)) {
        call = list_get_instance(queued_calls.next, async_call_t,
                     list);

        callid = _ipc_call_async(call->u.msg.phoneid,
                     &call->u.msg.data);
        if (callid == IPC_CALLRET_TEMPORARY)
            break;
        list_remove(&call->list);

        if (callid == IPC_CALLRET_FATAL) {
            futex_up(&ipc_futex);
            call->callback(call->private, ENOENT, NULL);
            free(call);
            futex_down(&ipc_futex);
        } else {
            call->u.callid = callid;
            list_append(&call->list, &dispatched_calls);
        }
    }
    futex_up(&ipc_futex);
}

/** Handle received answer
 *
 * TODO: Make it use hash table
 *
 * @param callid Callid (with first bit set) of the answered call
 */
static void handle_answer(ipc_callid_t callid, ipc_call_t *data)
{
    link_t *item;
    async_call_t *call;

    callid &= ~IPC_CALLID_ANSWERED;
    
    futex_down(&ipc_futex);
    for (item = dispatched_calls.next; item != &dispatched_calls;
         item = item->next) {
        call = list_get_instance(item, async_call_t, list);
        if (call->u.callid == callid) {
            list_remove(&call->list);
            futex_up(&ipc_futex);
            call->callback(call->private, 
                       IPC_GET_RETVAL(*data),
                       data);
            return;
        }
    }
    futex_up(&ipc_futex);
    printf("Received unidentified answer: %P!!!\n", callid);
}


/** Wait for IPC call and return
 *
 * - dispatch ASYNC reoutines in the background
 * @param data Space where the message is stored
 * @return Callid or 0 if nothing available and started with 
 *         IPC_WAIT_NONBLOCKING
 */
ipc_callid_t ipc_wait_for_call(ipc_call_t *call, int flags)
{
    ipc_callid_t callid;

    do {
        try_dispatch_queued_calls();

        callid = __SYSCALL2(SYS_IPC_WAIT, (sysarg_t)call, flags);
        /* Handle received answers */
        if (callid & IPC_CALLID_ANSWERED)
            handle_answer(callid, call);
    } while (callid & IPC_CALLID_ANSWERED);

    return callid;
}

/** Ask destination to do a callback connection
 *
 * @return 0 - OK, error code
 */
int ipc_connect_to_me(int phoneid, int arg1, int arg2, ipcarg_t *phone)
{
    return ipc_call_sync_3(phoneid, IPC_M_CONNECT_TO_ME, arg1,
                   arg2, 0, 0, 0, phone);
}

/** Ask through phone for a new connection to some service
 *
 * @return new phoneid - OK, error code
 */
int ipc_connect_me_to(int phoneid, int arg1, int arg2)
{
    ipcarg_t newphid;
    int res;

    res =  ipc_call_sync_3(phoneid, IPC_M_CONNECT_ME_TO, arg1,
                   arg2, 0, 0, 0, &newphid);
    if (res)
        return res;
    return newphid;
}

/* Hang up specified phone */
int ipc_hangup(int phoneid)
{
    return __SYSCALL1(SYS_IPC_HANGUP, phoneid);
}

int ipc_register_irq(int irq, irq_code_t *ucode)
{
    return __SYSCALL2(SYS_IPC_REGISTER_IRQ, irq, (sysarg_t) ucode);
}

int ipc_unregister_irq(int irq)
{
    return __SYSCALL1(SYS_IPC_UNREGISTER_IRQ, irq);
}

int ipc_forward_fast(ipc_callid_t callid, int phoneid, int method, ipcarg_t arg1)
{
    return __SYSCALL4(SYS_IPC_FORWARD_FAST, callid, phoneid, method, arg1);
}


/** Open shared memory connection over specified phoneid
 *
 * 
 * Allocates AS_area, notify the other side about our intention
 * to open the connection
 *
 * @return Connection id identifying this connection
 */
//int ipc_dgr_open(int pohoneid, size_t bufsize)
//{
    /* Find new file descriptor in local descriptor table */
    /* Create AS_area, initialize structures */
    /* Send AS to other side, handle error states */

//}
/*
void ipc_dgr_close(int cid)
{
}

void * ipc_dgr_alloc(int cid, size_t size)
{
}

void ipc_dgr_free(int cid, void *area)
{

}

int ipc_dgr_send(int cid, void *area)
{
}


int ipc_dgr_send_data(int cid, void *data, size_t size)
{
}

*/